Embodiments relate to an image sensor and a method of manufacturing an image sensor.
CMOS image sensors may have a structure in which photodiodes and transistors are horizontally disposed. While drawbacks of CCD image sensors may be addressed by related horizontal type CMOS image sensors, related horizontal type CMOS image sensors may have limitations. Photodiodes and transistors may be horizontally disposed adjacent to each other on and/or over a substrate. Accordingly, an additional region may be required for a photodiode, and thus there may be a limitations including relative reduction of a fill factor region and/or relative restriction of resolution.
It may also be relatively difficult to achieve optimization in reference to a process of manufacturing a photodiode and a transistor simultaneously. In a relatively quick transistor process, a shallow junction may be required for a low sheet resistance, but a shallow junction may not be appropriate for a photodiode. As additional on-chip functions are added to a horizontal type CMOS image sensor, the relative size of a unit pixel may need to relatively increased to maintain sensitivity of an image sensor, and/or may need to be relatively reduced to maintain an area of a photodiode to be a pixel size. If a pixel size increases, a resolution of an image sensor may be minimized, and if an area of a photodiode is relatively reduced, the relative sensitivity of an image sensor is minimized.
Accordingly, there is a need for an image sensor, and a method of manufacturing an image sensor, which may substantially relatively reduce an optical path, enhance photosensitivity, maximize resolution and/or maximize sensitivity.